Drying-tunnel



F. H. SMITH. DRYING TUNNEL.

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UNITED STATES PATENT OFFICE.

FRANCIS H. SMITH, OF BALTIMORE, MARYLAND.

DRYINGr-TUNNEL.

Specification forming part of Letters Patent No. 31,566, dated February26, 1861; Reissued June 30, 1868, No. 3,017.

To all whom it may concern:

Be it known that I, FRANCIS Il. SMITH, of the city of Baltimore andState of Maryland, have invented a useful Improvement in Drying-Tunnels;and I do hereby declare that the following is a full, clear, and exactdescription of t-he same, reference being hadto the accompanyingdrawings, forming a part of this specification, in which- Figure 1represents a longitudinal vertical, Fig. 2 a horizontal, and Fig. 3 avertical cross section of my drying tunnel. Fig. 4 is a perspective viewof one vof the trays, hereinafter described. Fig. 5 is a perspectiveview of a car with its complement of trays.

Similar letters of reference, in each of the several figures, indicatecorresponding parts.

The nature of my invention consists in a tunnel having a furnace or itsequivalent at the rear end and a chimney at the front end, incombination with gates, cars, trays and inclined rails, constructedsubstantially as and for the purposes hereinafter described.

The whole apparatus is intended for drying brick, fruit, &c., by meansof cars loaded with trays upon which the articles to be dried are piled,the cars traveling through a heated tunnel. The apparatus is so arrangedthat the drying tunnel and loading of the cars can go on uninterruptedlyfor any length of time.

To enable others, skilled in the art, to make and use my invention, Iwill proceed to describe its construction and operation.

A, B, C, represent a tunnel of considerable length (say 300 feet) madeof brick work or other suitable material. The rear and front end of thetunnel are provided with gates I-I, F, which can be closed or opened asmay be necessary in the course of the operation. The front portion A, ofthe tunnel may be cut off from the main part of the tunnel by means of agate G, which is represented half open in Fig. l. The section A,communicates with a chimney L, while the rear end C, of the tunnelcommunicates through an opening D, with a furnace R, provided with asuitable grate O.

A railway is laid on the floor of the tunnel, the rails E, E, beingsomewhat inclined from the front toward the rear of the tunnel.

A number of cars-enough to iill the whole length of the tunnel-areprovided and are to be loaded one after the other, with trays I, uponwhich the articles to be dried are placed. The said trays areconstructed as clearly shown in Fig. 4, having each four legs e',fitting in cavities z", in the upper corners of the tray below. Thisconstruction is needful in order to enable the trays to stand securelyin four separate stacks as represented in Fig. 5, with a space betweentheir edges to facilitate handling. The first car having been freightedin this manner, while in section A, of the tunnel, the gate F, is shutand gate G, is openedras seen in Fig. l-and the car is pushed into themain part B, of the tunnel, so that the gate G, can be shut behind it.The gate F, is then opened, the next car is entered into section A, andafter having been freighted in the same manner as the preceding car, the

gate G, is again opened and the car is moved forward into section B,pushing the first car forward. The gate G, is then again shut, gate F,is opened, and the third car is entered and freighted and so forth, eachcar pushing forward the preceding series of cars, as it enters the mainpart B, of the tunnel until the car which had been entered first,arrives at the end C, of the tunnel. The gate H, is then opened as oftenas a car is entered, in order to allow the last car of the series topass out of the tunnel. The heated gases arising from the combustion offuel in furnace R, enter through opening D, and pass through the wholelength of the tunnel and finally out at the chimneyA L. From this, itwill be seen that the substances to be dried, enter the tunnel at theend where the temperature is lowest and are gradually subjected to anincreasing heat as they approach the other end of the tunnel where theyfinally come in contact with the intense heat arising directly from thefurnace. `It is intended that about twenty-four hours shall elapse fromthe entrance to the exit of each particular car, thereby giving ampletime for drying the articles with which the cars are freightedthoroughly while they pass through the entire length of the tunnel.

The rails E, E, are inclined as shown in Fig. 1 so that the whole seriesof cars can be pushed along easily by the operator or operatorsattending the rear car.

The draft caused from the furnace R, through the whole length of tunneltoward `md out of the chimney L, serves to carry the moisture of thedrying articles away as fast as it is liberated; by Which means thedrying process is considerably facilitated.

Fig. 3 represents-at Q, R, D', S, P, N, M, K-a modification, asubstitute for the furnace R, to suit the apparatus for drying fruit,vegetables and similar articles. For this purpose, the opening D,connecting' the tunnel with the furnace R, is closed by means of asuitable valve orl damper S, and the valve Aor damper4 S, is opened soas to effect a communication between the rear part of the tunnelY and ahot air chamber R, through opening D. The air in this chamber is heatedby means of a suitable hot air furnace Which consists of a drum K,spiral hot air passage N, central fire place M, and smoke stack Q. Thehot air passes from the ydrum through P into chamber R, and hencethrough opening D', into the tunnel, obeying the draft created by thechimney L, at

the front end and thereby drying the ari ticles upon the Ashelves andcars passing and other chemicals.

lWhat I claim as my invention and desire to secure by Letters Patent,is-

A tunnel A, B, C, having a its equivalent at the rear end, and a chimneyL, at the front end, in combination with gates F, G, H, car J, trays I,and inclined rails E, E, the Whole being constructed and arrangedsubstantially as and for the purposes set forth. Y

` FR. H. SMITH. Witnesses:

R. M. PROUD, JOHN H. RoszEL.

furnace R, 0r y

